The objective of the Biostatistics and Data Management Core (Core B) of the Microbiota Allergy and Asthma Precision Prevention (MAAP2) P01 renewal application is to support the development and conduct of the four Projects and the four additional Cores. The expertise provided by Core B will aid all four Projects, allowing them to be efficiently and rigorously designed, conducted, monitored, and analyzed. Core B will also help ensure the timely and accurate acquisition and merging of data, and its dispersion to the various Projects, as well as maintaining data integrity for long term storage. Building upon a robust structure of Core B and integration with all of the Projects and Cores established during the initial funding period, the MAAP2 Core B Specific Aims are to: 1) continue to maintain and extend database infrastructure from the initial funding period to allow for efficient, accurate, and secure data storage and retrieval; 2) assure data integrity by scheduled review of data via checking distributions for unusual values (outliers), cross-checking groups of variables for internal consistency, and performing appropriate quality checks; 3) supply accurate, up-to-date, and well- documented files for analysis to the Projects; 4) perform the selection of study participants for the nested case- control study (Project 1), as well as samples based on maternal risk (Projects 2 and 3); 5) provide statistical methodological development and expertise on innovative statistical methods for designing and analyzing the various studies in MAAP2; 6) collaborate with investigators in the preparation of manuscripts and abstracts by performing and providing written summaries of analyses with interpretations to aid in inference; and 7) apply the highest standards of reproducible research by maintaining all analysis plans and using the most up-to-date methods for analysis code and data documentation for publication with manuscripts. To address these Specific Aims, Core B will rely on and extend infrastructure and tools it has developed and implemented during the initial P01 funding period. This list includes: 1) robust database systems including the Lab Sample Tracking and Routing Website, which has resulted no misplaced or lost samples to date; 2) a regular schedule of collaborative meetings with all Projects and Cores to ensure that all investigators and Core members are kept up-to-date with data processing, sample selection, and analyses, as well as to discuss the development of abstracts and manuscripts; 3) automated quality checks of data and documentation of those checks; 4) an analysis request and history tracking system to provide the highest level of transparency to the scientific community. Over the previous five years, Core B members have also developed expertise in the analysis of microbiome data by keeping up-to-date with the methods in the literature. Core B members will continue to do so to provide the most cutting edge and rigorous methods of analysis for each of the studies.